492212: [release] release Mylyn 3.20 (update version)

Change-Id: Iff1ee86db79517c7da92e1dbb4b8decfe54f6c27
Task-Url: https://bugs.eclipse.org/bugs/show_bug.cgi?id=492212
Signed-off-by: Frank Becker <eclipse@frank-becker.de>
40 files changed